suprasoup

What's up,

I am running the tt ecu mod and I was successfully running the vvti coils with the tach working by jumping the resistor on the back of the cluster. However after swapping to the new smart coils the tach is no longer working. The car runs perfect but no tach. I joined all 6 IGF wires into 1 and ran it to the original pin location 58.

Anyone have any idea why my tach is not working and suggestions on how to resolve?

My car is a 93 by the way.

Thanks

Ali SC3

iTrader: (10)

There should be a tach wire that was going to the old ignitor, I would try jumping it to the IGF and see if you can get a signal that way.
On the old safc's etc.. you get rpm by tapping into the IGF wire, so it should work.

suprasoup

Ok, cool. I'll give that a shot.

Do you happen to know what pin the tach wire is on the ecu plug?

Thanks

*Edit*

I found it, it's E10(A) pin 16 on the input plug for anyone else that may want to know.

Ali SC3

iTrader: (10)

Let us know how it works, I have told people about it before but no one reports back anymore. pretty sure it works though lol.

suprasoup

So I jumped pin 16 (tach) to pin 58 (igf) and still no go. It worked perfectly fine before the coil swap could it be the jumper wire needs to be removed from the back of the tach?

I lied, I realized I tapped pin 15. The only reason this happened is because the 2jzge harness does not have anything in E10 pin 16. So I will do some more research and maybe put a pin into 16 and tap it to the igf?

I don't want to go around poking new leads into the harness and expecting it to work. What do you think?

Thanks

suprasoup

https://www.supraforums.com/threads/...1-1101.839329/

This link pretty much answered my questions. I'm going to attempt this and report back.

Thanks.

Ali SC3

iTrader: (10)

The tach wire goes straight to the cluster from the ignitor on our cars (GE), the ecu calculates rpm itself (GE).
There should have been a tach wire and an IGF wire where the old ignitor was, just jump them right there as a test.

Or you could re-route that tach wire back to the ecu and connect it to GTE tach pin or IGF pin on ecu.
Or you should be able to catch that tach wire at the body plug by the ecu (where it is going from cluster through engine harness to the ignitor), and then take it from there to ecu tach or IGF.

Connecting the gte ecu tach pin to gte ecu IGF pin won't do anything, you need to connect the tach wire *coming from the cluster* to one of those 2 spots on the ecu or anywhere there is an IGF.

suprasoup

So I traced the tach wire from the ignitor to inside car that goes to a body plug that I assume leads to the tach. I tapped into the igf wire and when I start the car the tach will jump slightly to about 200 rpm for a sec then stop working.

Any ideas not sure why it wouldn't work if I'm getting the signal directly from the igf to what I believe is the tach (the tach did start moving so I'm pretty sure I'm tapping the right pin).

suprasoup

I also tried using e10 pin 16 still did not work. After looking more into this from my research the aristo gte ecu does not send a tach signal from the ecu. Is it possible when I tapped the tach into that pin it maybe broke it?

*Update*
To ensure I was tapping into the tach I ran a wire from the old vvti ignitor straight to igf on the ecu and still no go.

Cluster still works but no tach.

Ali SC3

iTrader: (10)

I don't think you would have damaged the tach but it is hard to say. I am not sure if some of the gte ecu's have a tach output and some don't, I know the gte ignitor has a tach pin that is unused on some models so I would think it is used on others.

Maybe there is something different about the 1zz IGF signal, I would try and search for that more online. I can't imagine it needing the tach mod to be undone to work now, but I guess that is a possibility.

suprasoup

Yeah, I have tried hooking it up enverway I could think. I tried feeding the igf and then the ecu tach signal to the tach pin in the diagnostic box. I noticed I get no reaction from the tach when I am trying to get the signal from the ecu tach pin. I only get the tach to jump when connecting to the igf signal.

I looked online and all the examples of people running 1zz/smart coils are using a standalone setup. So I can't find any real examples of someone doing this on the stock ecu and retaining the tach.

If someone has then please chime in.

suprasoup

I guess worst case scenario I can buy a tach adapter. But I would rather not if at all possible.

suprasoup

I guess worst case scenario I can buy a tach adapter. But I would rather not if at all possible.

suprasoup

So I did soon be more testing and the ecu pin e10 16 gives off a 5v signal and so does the igf wire. Anyone know what kind of signal the ignitor gives off?

Any recommendations on a tach adapter?

Ali SC3

iTrader: (10)

I was actually trying to find a waveform for the ignitor tach output on the newer ignitors, or the older ones for that matter but can't seem to find them.
Guess it is sounding like there is a big enough difference between the IGF and tach wires then, odd that some piggybacks can use either but maybe they can accept a wider range of input for tach than the stock cluster.
Probably just need an adapter then, it should be able to pick rpm up from IGF like the piggybacks. I haven't used one before so can't recommend a specific one, but it would be similar to any used on the gte also.

probably could guess what the waveform looks like from standalones that are setup to ouput the tacho, might lead you to the adapter you need.

And for the pinouts, looks like there is only the tach pin on the supra ecu, the aristo seems to have it labeled as timing retard so would not give a tach output.
Maybe if you can find a supra ecu that might also do the trick.